To understand the changes in yield, harvest index （HI） and biomass of aboveground parts of rice, 33 japonica rice cultivars released from 1958 to 2005 were planted. During the 47 years, the grain yield increased fro...To understand the changes in yield, harvest index （HI） and biomass of aboveground parts of rice, 33 japonica rice cultivars released from 1958 to 2005 were planted. During the 47 years, the grain yield increased from 9 118.36 to 15 060.1 kg/hm2 and HI from 0.46 to 0.55. In the genetic improvement, the total number of tillers per plant decreased, and the biomass per unit area slightly increased at the harvest stage. The increases of yield and HI resulted from the increased biomasses of effective tillers and single stem, and the increase of biomass per stem was related to the increased biomasses of different organs along with the genetic improvement. The stem and sheath biomass at heading and the leaf biomass at 30 days after heading showed the highest increase, up by 75.17% and 49.94%, respectively. The biomasses of leaf and stem-sheath at 10 days after heading, and biomass per stem at 30 days after heading were obviously correlated with the yield. The results indicate that the genetic improvement has resulted in the increase of yield and HI. This increase is correlated with the decrease of total tiller number per plant, and increase of biomasses of effective tillers and single stem. The leaf biomass after heading and the stem and sheath biomass at 10 days after heading can be used as selection criteria for breeding high yielding rice cultivars.展开更多
The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on co...The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on cold tolerance and its related physiological parameters in rice seedings （chilling-sensitive cv. Changbai 9 and chilling-tolerant cv. Jijing 81） under low temperature stress. At the same time, the identification of cold tolerance was conducted. Compared with the normal temperature treatment, the relative chlorophyll content, photosynthesis rate, Fv/Fm and qP decreased and index of unsaturated fatty acid increased in rice under low temperature stress. The effect of chilling-sensitive cultivars was more than that of chilling-tolerant cultivars, more phosphorus fertilizer properly improved seedling quality of rice, slowed relative chlorophyll content dropping degree of rice seeding, increased photosynthesis rate, Fv/Fm, qP and index of unsaturated fatty acids, and enhanced the ability to chilling-tolerant cultivars under low temperature. The effect on chilling-tolerant cultivars was significantly higher than that on chilling sensitive cultivars by applying more phosphorus fertilizer. Phosphate regulated photosynthetic physiology and membrane fluidity to reduce injury by low temperature, and increasd the cold tolerance capacity of rice.展开更多
基金supported by the National Jump Plan of Agriculture Science and Technology, China (Grant No. 200754)the Science and Technology Department of Key Projects of Jilin Province, China (Grant No. 20080201)
文摘To understand the changes in yield, harvest index （HI） and biomass of aboveground parts of rice, 33 japonica rice cultivars released from 1958 to 2005 were planted. During the 47 years, the grain yield increased from 9 118.36 to 15 060.1 kg/hm2 and HI from 0.46 to 0.55. In the genetic improvement, the total number of tillers per plant decreased, and the biomass per unit area slightly increased at the harvest stage. The increases of yield and HI resulted from the increased biomasses of effective tillers and single stem, and the increase of biomass per stem was related to the increased biomasses of different organs along with the genetic improvement. The stem and sheath biomass at heading and the leaf biomass at 30 days after heading showed the highest increase, up by 75.17% and 49.94%, respectively. The biomasses of leaf and stem-sheath at 10 days after heading, and biomass per stem at 30 days after heading were obviously correlated with the yield. The results indicate that the genetic improvement has resulted in the increase of yield and HI. This increase is correlated with the decrease of total tiller number per plant, and increase of biomasses of effective tillers and single stem. The leaf biomass after heading and the stem and sheath biomass at 10 days after heading can be used as selection criteria for breeding high yielding rice cultivars.
基金Supported by the Special Agricultural Project of Agricultural Department (200903003)the Agricultural Modernization Project in the Science and Technology Development Plan of Jilin Province (2009-2010) the High-yield Project of Science and Technology Department (2011BAD16B10)
文摘The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on cold tolerance and its related physiological parameters in rice seedings （chilling-sensitive cv. Changbai 9 and chilling-tolerant cv. Jijing 81） under low temperature stress. At the same time, the identification of cold tolerance was conducted. Compared with the normal temperature treatment, the relative chlorophyll content, photosynthesis rate, Fv/Fm and qP decreased and index of unsaturated fatty acid increased in rice under low temperature stress. The effect of chilling-sensitive cultivars was more than that of chilling-tolerant cultivars, more phosphorus fertilizer properly improved seedling quality of rice, slowed relative chlorophyll content dropping degree of rice seeding, increased photosynthesis rate, Fv/Fm, qP and index of unsaturated fatty acids, and enhanced the ability to chilling-tolerant cultivars under low temperature. The effect on chilling-tolerant cultivars was significantly higher than that on chilling sensitive cultivars by applying more phosphorus fertilizer. Phosphate regulated photosynthetic physiology and membrane fluidity to reduce injury by low temperature, and increasd the cold tolerance capacity of rice.
